The preferred embodiment relates to an arrangement and a method for cooling a power semiconductor, in which at least one electrical terminal of the power semiconductor is electrically conductively connected to the electrical terminal of a passive component.
Known circuits comprising power semiconductors are often implemented with the aid of printed circuits in which power semiconductors of the SMD type are used. The heat generated as a result of power loss when a current flows through the power semiconductor has to be dissipated in order to prevent that an allowable temperature limit is exceeded and that the power semiconductor is thus destroyed. In particular in the case of surface mount power semiconductors, the mounting of cooling elements is relatively complex. Further, surface mount power semiconductors have a low height, as a result of which cooling elements, such as heat sinks, mounted on the power semiconductor are likewise arranged at a short distance to a printed circuit. This short distance has the effect that air flowing around such a cooling element is impeded by components arranged next to the power semiconductor on the printed circuit.
Further, arrangements for cooling a power semiconductor are feasible, in which conductive areas of the printed circuit are formed and utilized as cooling surfaces for dissipating heat. However, here too, there is the problem that components arranged on the printed circuit impede the circulation of air required for dissipating the heat from these areas. Depending on the amount of heat generated by the power semiconductor, such an arrangement also requires that large areas of the printed circuit are provided as cooling surfaces. These cooling surfaces take up a relatively large space.
By means of through-hole connections, several so-called layers of printed circuits, as known, for example, from multilayer printed circuit boards, can be used as cooling surfaces. However, then too, a relatively large space is required so that sufficient heat can be dissipated. Further, in particular in the case of high-frequency switching events affected with the aid of the power semiconductor the large conductive areas of the printed circuit may act as antennas, as a result of which undesired interference effects may occur. These interference effects particularly cause an inadmissible electromagnetic radiation. In order to avoid interferences caused by EMC radiation (EMC=electromagnetic compatibility), the conduction paths between individual components should be as short as possible. Especially in the case of switching mode power supplies having power semiconductors operated at high switching frequencies an electromagnetic radiation is radiated over long or large-area electrical interconnection conductors and this radiation is outside the acceptable ranges of electromagnetic radiation.
From documents WO 01/20955 A1, JP 2002-222720A, U.S. Pat. No. 6,366,486 B1 and JP 2000-299524A, arrangements for dissipating the heat generated by power semiconductor components that are arranged on printed circuits are known.